Treatment method for urban waste incineration residues and products thus obtained

Abstract

The invention relates to a treatment method for urban waste incineration residues in a finely divided form, in which the residues to be treated are homogenized and their composition is subjected to a chemical analysis. Then, the residues are mixed with water and a reagent containing active alumina in proportions determined in relation to the chemical analysis of the residues, in order to generate complex aluminates, whereas active alumina is in excess.

We claim: 
     
       1. A method of treating urban waste incineration residues, in a finely divided form, comprising the steps of: a) homogenizing the residues to be treated;   b) chemically analyzing the composition of said homogenized residues to determine at least the calcium and soluble salts content thereof:   c) mixing said residues with water and a reagent containing a mixture of active alumina or compounds sufficient to release active alumina and lime in preset proportions determined in relation to the chemical analysis of the residues, in order to generate complex aluminates, wherein the active alumina of said reagent is in excess of that needed to generate said complex aluminates;   d) setting the mixture so as to harden.   
     
     
       2. Treatment method according to claim 1, characterised in that the reagent contains [CaO] 3  ]Al 2  O 3  ]. 
     
     
       3. Treatment method according to claim 1, characterised in that the reagent contains [CaO] 12  ]Al 2  O 3  ] 7 . 
     
     
       4. Treatment method according to claim 1, characterised in that the reagent contains both [CaO] 3  ]Al 2  O 3  ]and [CaO] 12  ]Al 2  O 3  ] 7 . 
     
     
       5. Treatment method according to claim 1, characterised in that, during stage b), at least some of the chlorides, sulphates, carbonates and nitrates are analysed. 
     
     
       6. Treatment method according to claim 1, characterised in that the excess of active alumina is comprised between 0 and 20%. 
     
     
       7. Treatment method according to claim 1, characterised in that, after stage d): e) the granulometry of the solid obtained is adapted in order to produce a granulate;   f) the granulate is mixed to a binding agent, in order to form a solid, in which the granulate is embedded.   
     
     
       8. Treatment method according to claim 7, characterised in that the binding agent is a hydraulic one. 
     
     
       9. Treatment method according to claim 8, characterised in that the binding agent is a Portland cement. 
     
     
       10. Treatment method according to claim 7, characterised in that the granulate/binding agent mixture is shaped up before solidification. 
     
     
       11. Treatment method according to claim 7, characterised in that the granulate/binding agent mixture is pressed. 
     
     
       12. Treatment method according to claim 7, characterised in that the granulate/binding agent mixture is vibrated. 
     
     
       13. Products obtained by implementing the process according to any of the claim 1. 
     
     
       14. A method for treating urban waste incineration residues comprising the steps of: (a) homogenizing the residues to form homogenized residues;   (b) analyzing the homogenized residues to determine at least the calcium content or soluble salt content of the residues;   (c) mixing the residues with water and a reagent containing compounds capable of forming complex aluminates to form a mixture wherein the compounds are in an amount in stoichiometric excess of that needed for the formation of said complex aluminates; and   (d) reacting the mixture to form complex aluminates and thereby harden the residues.   
     
     
       15. The method as recited in claim 14, wherein the reagent comprises [CaO] 12  [Al 2  O 3  ] 7 . 
     
     
       16. The method as recited in claim 14, wherein the reagent comprises [CaO] 3  [Al 2  O 3  ]. 
     
     
       17. The method as recited in claim 14, wherein the reagent comprises [CaO] 3  [Al 2  O 3  ]and [CaO] 12  [Al 2  O 3  ] 7 . 
     
     
       18. The method as recited in claim 14, wherein the reagent is added at a weight excess between 0 and 20%. 
     
     
       19. The method as recited in claim 14, wherein maximum fixation of the soluble salts in the form of aluminates is achieved. 
     
     
       20. The method as recited in claim 14, wherein lime is added with the water and reagent to the mixture of step (c).